Giphy's big library of looping quick video animations is vastly famous in Facebook's apps.
But it additionally presents animations to rivals like TikTok, Snapchat and Twitter.
Now, the UK Competition and Markets Authority (CMA) is investigating whether or not the buy is a problem.
It has despatched an enforcement order to Facebook, successfully inserting a maintain on any merging of the businesses till its investigation is over.
Announcing the acquisition in May this year, Facebook stated that 1/2 of Giphy's site visitors comes from Facebook apps, such as Whatsapp and Instagram.
But it additionally stated that the deal - well worth a said $400m (£317m) - would now not have an effect on offers in area with different partners.
The CMA, however, stated it was once investigating whether or not or no longer the acquisition "may be anticipated to end result in a sizable lessening of competition".
It is inviting feedback till three July, with no date set for its decision.
But the enforcement capability Facebook has to maintain the Giphy company, staff, and science separate from Facebook itself - except it receives develop written permission from the CMA.
Facebook says it plans to roll the organisation into its Instagram team, the place the "stickers" Giphy presents are most popular.
A Facebook organisation spokesperson stated that Giphy "improves Instagram's choices through giving humans greater aspects and tools".
They additionally reiterated the company's preceding stance that different businesses which use Giphy would now not lose any get admission to to the platform.
"We are organized to exhibit regulators that this acquisition is superb for consumers, builders and content material creators alike," they said.
The merger of Facebook and Instagram was once investigated returned in 2012 by way of the Office of Fair Trading, which used to deal with such issues. It selected no longer to pursue the rely any further.
It is now not the first time issues have been raised about the Facebook-Giphy deal, with questions raised over what stage of get right of entry to Facebook would have to its competitor's facts via the service.
In May, quickly after the announcement, some US senators informed the Verge they had such concerns.
The Republican Senator for Missouri, Josh Hawley, said: "Facebook continues searching for even extra approaches to take our data… Facebook desires Giphy so it can gather even extra facts on us."
